1. Field of the Invention
The present invention relates to an apparatus for regulating salt concentration using electrodialysis, a lab-on-a-chip including the same and a method of regulating salt concentration using the apparatus for regulating salt concentration.
2. Description of the Related Art
Due to recent developments in biotechnology, protein sequences and base pair sequences containing genetic information of individuals have been identified. Thus, many researchers have attempted to develop biochips, particularly, labs-on-chips, for analyzing base pair sequences, diagnosing diseases, etc.
A lab-on-a-chip is an automated and micronized chip that can process the following experimental procedures in situ: extracting a biomolecule such as deoxyribonucleic acid (DNA), ribonucleic acid (RNA) or a protein from a sample containing cells; amplifying the extracted biomolecule; hybridizing the amplified biomolecule to a previously immobilized biomolecule; detecting the hybridized result; and providing quantitative analysis of the experimental results.
Generally, a lab-on-a-chip includes: an extraction chamber in which a biomolecule is extracted; an amplification chamber in which the extracted biomolecule is amplified; a hybridization chamber in which the amplified biomolecule is hybridized to biomolecules immobilized in the hybridization chamber; a detection chamber in which whether hybridisation has occurred or not is detected; and micro-channels connecting the above-described chambers. In the extraction chamber, cells in a sample are enriched and lysed to purify a biomolecule therefrom. In the amplification chamber, a biomolecule is amplified through, for example, a polymerase chain reaction (PCR). A biomolecule with known base pair sequences is immobilized on a side of the hybridization chamber, and hybridization between the immobilized biomolecule and the amplified biomolecule occurs in the hybridization chamber. The degree of the hybridization is measured in the detection chamber.
The lab-on-a-chip requires different salt concentrations at each operation stage, including an enrichment stage, a lysis stage, a purification stage, an amplification stage, a hybridization stage, a washing stage, a drying stage, and a detection stage. Therefore, solutions with different salt concentrations are previously prepared and then injected individually into each operation chamber. Alternatively, when the operation stages are carried out in one chamber, solutions with different salt concentrations are injected for each operation stage.
FIG. 1 illustrates a conventional apparatus for injecting solutions with different salt concentrations into a reaction chamber 101 of a lab-on-a-chip.
Referring to FIG. 1, the reaction chamber 101 where each reaction such as hybridization takes place is connected to first through fifth pumps 102, 103, 104, 105, and 106 through a channel 116. The first pump 102 pumps a washing buffer solution. The second through fourth pumps 103, 104 and 105 pump solutions with different salt concentrations. The fifth pump 106 pumps a sample solution with a biomolecule. The washing buffer solution, which does not include salt, and the solutions with the different salt concentrations are injected into the reaction chamber 101 by adjusting the flow from the first through fifth pumps 102, 103, 104, 105, and 106 with first through fifth valves 107, 108, 109, 110, and 111. The used solutions are discharged into storage units 114 and 115 by adjusting a sixth valve 112 and a seventh valve 113.
However, the above described conventional apparatus needs many parts including the pumps, the valves, the channel, and the storage units, and thus, the apparatus may be complicated. For each operation stage, the pumps and the valves are operated to inject and discharge each solution. Hence, an operation time may be long.